This is a study of the physical chemistry of DNA, with particular emphasis on its hydrodynamic behavior and on its behavior as a polyelectrolyte. We shall try to elucidate the mechanism of the breakage of DNA in mechanically sheared solutions, particularly with respect to the effects of various ions, of varying DNA molecular weight, and of changes in the flow regime. We shall study theoretically the nature of the counter-ion distribution around long thin charged cylinders of finite length as models for DNA. We are investigating improvements in the methods of calculating the hydrodynamic (sedimentation, viscosity, rotational diffusion) properties of long flexible charged molecules such as DNA. If time permits we expect to work on the theory of spin resonance in such molecules.